Prowler, Clawed Thief is a uncommon Legendary Creature — Human Rogue Villain card from Through the Omenpaths (OM1), collector number 128.
Menace (This creature can't be blocked except by two or more creatures.) Whenever another Villain you control enters, Prowler connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)